The present invention relates to a method of inspecting defects in a semiconductor device. More particularly, the present invention relates to a method of inspecting defects in a semiconductor device, which method can be performed electrically during the manufacturing process.
In general, a semiconductor device formed in a silicon wafer includes isolation regions for electrically isolating respective semiconductor devices. As semiconductor devices are highly integrated and have become micro, active research has been made to shrink the size of an individual device and also to reduce the isolation region. This is because the formation of the isolation region is an early process step of the entire manufacturing steps and decides the size of an active region and process margin of subsequent process steps.
Isolation layers are formed in the isolation region using a method, such as shallow trench isolation (STI). According to the STI method, a nitride layer with an etch selectivity different from that of a semiconductor substrate is first formed on the semiconductor substrate. The nitride layer is patterned in order to use the nitride layer as a hard mask, thus forming a nitride layer pattern. The semiconductor substrate is etched to a predetermined depth by an etch process using the nitride layer pattern as a hard mask, thereby forming trenches. The trenches are gap-filled with insulating materials, for example, a high-density plasma (HDP) oxide layer, an O3-TEOS oxide layer, etc. A polishing process, such as chemical mechanical polishing (CMP), is performed on the oxide layer formed over the semiconductor substrate, so that the isolation layers are formed in the trenches.
However, in the technology of 80 nm or less level, the aspect ratio of the trench is increased in line with micro process technologies. Consequently, void is generated due to the limited characteristics of an oxide layer to gap-fill the trench and, therefore, the isolation layer defective. Due to the defective isolation layer, an insulating characteristic of a corresponding semiconductor device is degraded and the corresponding semiconductor device can fail. Accordingly, it becomes important to perform a process for finding defective semiconductor devices by inspecting for the defects.